For glass packaging, the factors affecting the strength of glass fiber:
1.Effect of fiber diameter and length on tensile strength
In general, the smaller the diameter of the glass fiber, the higher the tensile strength, but the strength of the fiber of the same diameter drawn at different drawing temperatures may also be different. The tensile strength of glass fiber is related to the length. The increase in tensile strength significantly decreases the impact of diameter and length on the tensile strength of glass fibers, which can be explained by the micro-crack hypothesis. Because as the fiber diameter and length decrease, the micro-cracks in the fiber will correspondingly decrease, thereby increasing Fiber strength.
2. The influence of chemical composition on strength
Generally, the higher the alkali content, the lower the strength. The alkali-free fibers have 20% higher tensile strength than the alkali-fibers. Studies have shown that high-strength and alkali-free fibers, due to high molding temperature, fast curing speed, and large structural chain energy, etc. Therefore, it has a high tensile strength. Glass fibers containing many K2O and PbO components have low strength.
3.Effect of glass liquid quality on glass fiber strength
A) The effect of crystalline impurities: When the glass composition fluctuates or the temperature of the leak plate fluctuates or decreases, it may cause the appearance of crystals in the fibers. Practice has proven that crystalline fibers have lower strength than non-crystalline fibers.
B) The small air bubbles in the glass liquid will also reduce the strength of the fiber. It has been tested that the glass fiber containing small air bubbles is drawn with a diameter of 5.7um, and the strength of glass fibers is 20% lower than that of fibers drawn with pure glass liquid.
Practice has proved that the strength of glass fiber drawn by the leaky plate is higher than that of the glass rod method. In the glass rod method, the fiber produced by heating with gas is stronger than the fiber produced by heating wire. The plate method is 10um, the strength of the glass fiber is 1700MPa, and the strength of the glass fiber with the same diameter drawn by the rod method is only 1100MPa. This is because the glass rod is only heated to soften, the viscosity is still large, and the fiber is subjected to great stress during drawing In addition, the glass rod method is drawn at a lower temperature, and the cooling rate is lower than that of the leak plate method. The strength of glass fibers produced by various molding methods is different. The strength of the fiber drawn by the leak plate method is more High, air blown and stretched cotton is second, glass rod method is the second. Then steam vertical blown short cotton, the lower strength is steam blown mineral wool. In the method of drawing the leaky plate, the higher molding temperature is used. The smaller the diameter of the leakage hole can improve the fiber strength.
5. The effect of surface treatment on strength
When continuous drawing, a single fiber or fiber bundle must be coated with an infiltrant, which forms a protective film on the surface of the fiber to prevent mutual friction between the fibers during the textile processing process, which damages the fibers and reduces the strength. After the heat treatment removes the sizing agent, the strength decreases a lot, but after treatment with the intermediate binder, the strength generally rises. This is because the intermediate binder coating protects the fibers on the one hand, and on the other hand Surface defects are made up.